1. Field of the Invention
The present invention relates to a tube connecting apparatus for heating and melting to cut flexible tubes and connecting the tubes by mutually welding the cut end faces thereof.
2. Description of the Related Art
According to a conventional tube connecting apparatus, two tubes, for instance, to be connected are held in parallel with each other and a cutting plate comprising a plate-like heating element is moved as if to cross the tubes, thereby heating and melting to cut the tubes. The tubes thus held are rotated so that the cut ends will slide on the cutting plate, and then the melted cut ends of the tubes are connected with each other by the withdrawal of the cutting plate.
A conventional example of a tube connecting apparatus having the above-described function, particularly a holder for holding tubes, will hereinafter be briefly explained. FIG. 28 is a perspective illustration showing a holder in use in a conventional tube connecting apparatus.
The tube connecting apparatus of the conventional example comprises a fixed tube holder 201 which is fixedly secured at all times, and a movable tube holder 202 which is rotatable and movable in the axial direction of tubes. The fixed tube holder 201 and the movable tube holder 202 are provided with grooves 231 and 241 in holder blocks 203 and 204 in which tubes 205 and 206 can be mounted. On the holder blocks 203 and 204, covers 207 and 208 are rotatably attached by hinges. Therefore, with the rotation of the covers 207 and 208, the grooves 231 and 241 of the holder blocks 203 and 204 are opened and closed. The fixed tube holder 201 and the movable tube holder 202 are provided with a locking mechanism. The lock mechanism is composed of engaging pawls 271 and 281 protrusively provided on the covers 207 and 208, and engaging holes 232 and 242 provided by drilling in the holder blocks 203 and 204 which engage with the engaging pawls 271 and 281.
The movable tube holder 202 is set a specific distance off the fixed tube holder 201, and the grooves 231 and 241 are positioned so as to be aligned on one line.
The movable tube holder 202 is provided with rotating means for rotating itself. This rotating means is formed such that the forward end of a crankshaft connected to a driving shaft of a motor 210 is secured to the holder block 204 of the movable tube holder 202. On the extension M of the driving shaft of the motor 210, the grooves 231 and 241 formed in the holder blocks 203 and 204 of the fixed tube holder 201 and the movable tube holder 202 are extendedly present, so as to be located on, or in the vicinity of, the tubes 205 and 206 which are charged one over the other within the grooves 231 and 241.
In the case of the conventional tube connecting apparatus of the above-described constitution, first the grooves 231 and 241 are opened by the user of the apparatus by turning the covers 207 and 208 upwards from the holder blocks 203 and 204 of the fixed tube holder 201 and the movable tube holder 202. Then, the tubes 205 and 206 are set one over the other in the grooves 231 and 241 thus opened upwards. Subsequently the covers 207 and 208 are turned downwards to close the grooves 231 and 241 with the tubes 205 and 206 thus set, and are held down until the engaging pawls 271 and 281 of the covers 207 and 208 are firmly engaged with the engaging holes 232 and 242 formed in the holder blocks 203 and 204.
Subsequently, after thus setting the tubes 205 and 206 on the tube connecting apparatus, the user depresses an unillustrated starting switch to ON, thereby connecting the cut ends of these tubes 205 and 206 by the above-described operation.
That is, when the switch is depressed to ON, an unillustrated cutting plate travels between the fixed tube holder 201 and the movable tube holder 202 to cut the tubes 205 and 206. After the cutting of the tubes 205 and 206, the movable tube holder 202 is turned 180 degrees up and down through the crankshaft 211 by turning power of the motor 210. Then, when the cutting plate is withdrawn, the movable tube holder 202 is axially moved by unillustrated moving means by the same amount as the thickness of the cutting plate towards the fixed tube holder 201, melting to mutually connect the cut ends of the tubes 205 and 206. At this time, as the tube holder 202 has been turned 180 degrees, the cover 208 faces down and the holder block 204 faces up.
Subsequently, the user opens the groove 231 by turning the cover 207 upwards from the holder block 203 of the fixed tube holder 201.
Thereafter, with the starting switch pressed to ON, the movable tube holder 202 is turned 180 degrees by the turning power from the motor 210 through the crankshaft 211. Then, as the cover 208 of the movable tube holder 202 faces up, the groove 241 is opened by turning the cover 208 upwards from the holder block 204, and the tubes thus connected are taken out.
The conventional tube connecting apparatus, however, has the following problems.
In the above-described conventional tube connecting apparatus, as the movable tube holder 202 has turned 180 degrees from the state before jointing, the cover 208 can not turn from the holder block 204 and accordingly the tubes can not be taken out after the tubes 205 and 206 are cut and jointed.
To take out the jointed tubes, the groove 231 is opened in advance by turning the cover 207 upwards from the holder block 203 of the fixed tube holder 201. Next, it is necessary to open the groove 241 of the holder block 204, after the cover 208 turns to face up, by operating the starting switch to turn the connected tube 180 degrees, together with the movable tube holder 202, and then to turn the cover 208 further upwards, making operation complicated and requiring much time for pipe connection.
Furthermore, in the conventional tube connecting apparatus, as described above, the apparatus automatically cuts and connects the tubes 205 and 206; and therefore the user himself is required to carry out setting the tubes 205 and 206 to, and taking out the tubes from, the apparatus.
In this case, it becomes necessary to open and close the covers 207 and 208 together with the fixed tube holder 201 and the movable tube holder 202. However, in order to prevent connection error likely to be caused by misalignment of the tubes 205 and 206, there is provided lock means which comprises the engaging pawls 271 and 281 and the engaging holes 232 and 242. Therefore a power is needed to open and close the covers 207 and 208 when the user sets the tubes 205 and 206 on the fixed tube holder 201 and the movable tube holder 202. To open and close the covers 207 and 208, about 1.5 to 2 kgf finger tip pressure is required.
This degree of pressure is liable to be thought not so great a pressure for a physically sound person, who therefore can easily open and close the covers 207 and 208. However, the present apparatus is used for connecting a transfer tube connected with the abdominal cavity to a tube connected with a dialysis pack to supply for instance a dialysis solution into the abdominal cavity of a peritoneum dialysis patient. Therefore, it is quite an easy operation to the physically sound person to open and close the covers 207 and 208. However, it is a hard work to such a physically handicapped person as a peritoneum patient who is weak-sighted or has a low physical strength.
Furthermore, in the conventional tube connecting apparatus described above, the tubes 205 and 206 are set one over the other in the grooves 231 and 241 formed in the holder blocks 203 and 204; therefore, the lower tube in the grooves 231 and 241, if pulled first by mistake after connection, will be caught by the upper tube, resulting in such a disadvantage as twist or damage.
Furthermore, there also occurs such a problem that if the movable tube holder 202 holding the tubes 205 and 206 is turned, the tubes will twist around the motor 210 mounted outside of the movable tube holder 202 and also around the crankshaft 211 transmitting the power from the motor 210 to the holder block 204.